1. Field of the Invention
The present invention relates to a miniaturized secondary-electron detector and a miniaturized electron-beam system such as a SEM (scanning electron microscope) using the same.
2. Description of the Related Art
When observing a minute sample or a minute pattern on a sample by a miniaturized electron-beam system, it is necessary to improve the resolving power by finely focusing the beam. If high energy, for example, a 50 kV beam is used, it is possible to finely focus the beam. To the contrary, with a miniaturized electron-beam system using a micro column (T. H. P. Chang et al., J. Vac. Scl. Technol. B, Vol. 14, No. 6, 3774, November/December 1966), if low energy, for example, a 1 kV beam is used, it is possible to finely focus the beam.
There are MCP (microchannel plate) and MSP (micro sphere plate) as a miniaturized secondary-electron detector used for a miniaturized electron-beam system.
However, since the MCP and MSP are constructed so that electrons incident to one side of a plate are multiplied to output electrons from the opposing side of the plate with voltage applied between the sides of the plate, they are too large as regards a miniaturized electron-beam system in which a lens having an bore diameter of 200 .mu.m or the like and a column 3.5 mm long or so are used. Although a multiple miniaturized electron-beam system in which a plurality of micro columns are arrayed has been proposed, they can not be applied to this system because the miniaturized secondary-electron detector is too large and one detector can not serve for a plurality of micro columns. Therefore, the miniaturized electron-beam system could be used for only micro lithography where the miniaturized secondary-electron detector is not used.